Optimized Multi-LNA Solution for Wideband Auxiliary Inputs Supporting Multiple Bands

ABSTRACT

A high performance low noise amplifier integrated circuit having multiple low noise amplifiers enabling operation over a wide range for frequencies is disclosed. In particular, an auxiliary input is provided to the low noise amplifier integrated circuit that can be routed to one of several low noise amplifiers, each tuned to operate efficiently in different frequency ranges.

BACKGROUND (1) Technical Field

The present disclosure relates to wideband low noise amplifiers, andmore particularly to a communications front-end module having multiplelow noise amplifiers for use with multiple frequency bands.

(2) Background

It is not uncommon for the operational specifications of somecommunication devices to require that the device receive and processsignals in both a first and at least a second relatively narrowfrequency band. In some cases, such frequency bands each have a centerfrequency that is relatively distant from one another. In some cases,inputs can be dedicated to one or more bands that are relatively closein frequency. However, in some cases it is desirable to have anauxiliary (AUX) input that is not designated for use by any particularfrequency band. Such AUX inputs can cover several bands within a widefrequency range. Providing such flexibility allows the same module to bereconfigured for use in several geographic regions and to be useful withfuture revisions. Accordingly, it is desirable for the AUX input to becapable of handling bands that fall over a relatively wide frequencyrange.

One solution that has been used in mobile front-end modules (FEMs) withlow noise amplifier integrated circuits (LNAIC) covering a widefrequency range is to provide a band-switching LNA. Such aband-switching LNA uses switchable caps to optimize the LNA performancebased on the desired band of operation. Band-switching LNAs have a sizeadvantage over front-ends that use more than one LNA to cover thefrequency range. However, the size advantage comes at the expense ofperformance. The performance degradation is due to the “off parasitics”of switchable caps used in such band-switching LNA designs. Theseparasitics have a negative impact on the high-frequency performance ofthe front-end. In addition, it is not possible to fully optimize eachband independently.

In another method, additional external inductor can be used forimpedance matching when operating at the lower frequencies. However,using such additional external inductor hurts the performance. Inparticular, the performance can suffer when such external inductor isused with additional routing capacitances in between matching inductorsin systems that have a characteristic routing impedance that differsfrom 50 ohms. Furthermore, such external components add additionalexpense to the overall design.

Accordingly, there is a need for a low cost, high performance FEM LNAIChaving AUX inputs that can receive inputs in several frequency bandsover a broad frequency range.

SUMMARY

The presently disclosed method and apparatus provides a front-end module(FEM) having a low noise amplifier integrated circuit (LNAIC) with anauxiliary (AUX) input that is concurrently coupled to at least two LNAs.Each of the LNAs is excited by the same input (e.g., an input applied tothe AUX input port) via a transmission line on the FEM substrate. Insome embodiments, the LNAs are tuned to two particular frequency bandsand are coupled to input ports dedicated to receive signals in thosefrequency bands. In an alternative embodiment, the AUX input is coupledto at least one additional LNA that has been tuned to receivefrequencies that the other LNAs (i.e., those tuned to service the otherinput ports) are not efficiently tuned to amplify.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of one example of a low noiseamplifier integrated circuit (LNAIC).

FIG. 2 is a slightly more detailed illustration of the LNAIC of FIG. 1.

FIG. 3 is a simplified block diagram of another embodiment of an LNAIC.

FIG. 4 is a more detailed illustration of the LNAIC of FIG. 3.

FIG. 5 is a flowchart illustrating a method for efficiently amplifyingsignals coupled to an auxiliary (AUX) input, wherein the signals can bein any frequency band selected from a broad range of frequency bands.

FIG. 6 is a flowchart of another method for efficiently amplifyingsignals coupled to an AUX input, wherein the signals can have anyfrequency from among a broad range of frequency bands.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a simplified block diagram of one example of a low noiseamplifier integrated circuit (LNAIC) 100. FIG. 1 also shows severalports 102, 104, 106, 108, 110 provided to allow external signal sourcesto be coupled to the LNAIC 100. The external sources are not shown andmay be any signal source, such as an antenna, transmission line, etc. Insome embodiments, the LNAIC 100 has two LNAs 112, 114. However, inalternative embodiments, several additional LNAs may be present withinthe LNAIC 100. Signals applied to the first, second and third port 102,104, 106 are coupled to a corresponding three “high-band” inputsHB_IN1-3 to the LNAIC 100. The first two ports 102, 104 are coupled tothe LNAIC 100 through respective bandpass filters 116, 118. In someembodiments, auxiliary (AUX) port 106 is coupled directly to twodifferent inputs HB_IN3 and LB_IN3 of the LNAIC 100.

The first port 102 is provided to allow signals within a predeterminedfrequency range matching the passband of the bandpass filter 116 to becoupled to the LNAIC 100. Signals coupled by the signal source to theport 102 that fall outside the bandpass of the bandpass filter 116 arerejected by the bandpass filter 116. Therefore, only those signalshaving frequencies that lie with the bandpass of the filter 116 will beeffectively coupled to the HB_IN1 input to the LNAIC 100. Accordingly,the port 102 is effectively dedicated to receive signals within thepassband of the filter 116.

The second bandpass filter 118 is tuned to have a passband that does notoverlap with the passband of the first bandpass filter 116. In someembodiments, the passband of the first and second bandpass filters 116,118 are relatively close to one another. Alternatively, the bandpass ofthe first filter 116 may overlap with the bandpass of the second filter118, but the passbands are not identical. That is, at least somefrequencies passed by one of the filters 116, 118 is rejected by theother.

The passband of each bandpass filter 116, 118 is tuned to passfrequencies for which the first of the two low noise amplifiers 120 isoptimized. In some examples, one LNA 120 is tuned to perform relativelybetter at higher frequencies. Thus, the LNA 120 is designated a“high-band” (HB) LNA. In some such embodiments, the second LNA 122 istuned to perform better at relatively lower frequencies. Thus, the LNA122 is designated a “low-band” (LB) LNA. The bandpass filters 130, 132coupled to the ports 108, 110 are tuned to pass frequencies for whichthe LB LNA 122 is optimized.

In some embodiments, the output of the HB bandpass filter 116 is coupledto a first input HB_IN1 of an HB band-select switch 124 having threeinputs HB_IN1-3. The HB band-select switch 124 selects one of the threeinputs HB_IN1-3 and couples the signals applied to the selected input toa band-select switch output 126.

Similarly, the outputs of each of the bandpass filters 130, 132 arecoupled to a “low-band” (LB) band-select switch 128. The LB band-selectswitch 128 has three inputs LB_IN1-3. The LB band-select switch selectssignals applied to one of the three inputs LB_(')IN1-3 to be coupled toa LB band-select switch output 134. The bandpass filter 130 is coupledto the LB_IN1 input. The bandpass filter 132 is coupled to the LB_IN2input.

As noted above, the signals applied to the first two inputs HB_IN1 andHB_IN2 of the HB band-select switch 124 and the first two inputs LB_IN1and LB_IN2 of the LB band-select switch 128 are filtered by the bandpassfilters 116, 118, 130, 132. However, the signals received through theinput port 106 (designated as an Auxiliary (AUX) input port in someembodiments) are directly coupled to the third input HB_IN3 of the HBband-select switch 124 and to the third input LB_IN3 of the band-selectswitch 128. The signals coupled from the AUX input 106 are not filteredprior to being coupled to the band-select switches 124, 128 to allowflexibility in the frequency range of the signals that are applied tothe AUX input 106. Furthermore, in some embodiments, when signals areapplied to the AUX input, no signals are applied to any of the otherports 102, 104, 108, 110. Accordingly, when signals applied to the AUXinput lie within the frequency range for which the HB LNA 120 isoptimized, those signals can be routed to the HB LNA 120. Alternatively,when the signals lie within a frequency range from which the LB LNA 122is optimized, the signals applied to the AUX input can be routed to theLB LNA 122. In other embodiments, the LNAIC 100 has an AUX input ratherthan an HB_IN3 input and an LB_IN3 input. The LNAIC 100 couples the AUXinput to inputs of each of the band-select switches 124, 128.

In some embodiments, a switch control processor 136 controls theband-select switches 124, 128. Further details regarding the switchcontrol processor 136 are provided below.

FIG. 2 is a slightly more detailed illustration of the LNAIC 100. Insome embodiments, each band-select switch 124, 128 is essentiallyidentical. However, in some embodiments, the switches 124, 128 may alsobe optimized for operation in the frequency range associated with theinput ports 102, 104, 108, 110 (see FIG. 1) from which they receivetheir respective signals. Therefore, for the sake of simplicity, thedetails of only the LB band-select switch 128 and the LB LNA 122 areshown and discussed.

The LB band-select switch 128 provides a path from one of the inputsLB_IN1-3 to an output 134 of the band-select switch 128. The path isestablished by closing one of three switches 203, 205, 207. For the sakeof simplicity each of the switches 203, 205, 207 are shown as simplesingle pole, single throw switches. However, in some embodiments, all ofthe switches in the LNAIC 100 are implemented using FETs that can beturned on to close the switch (i.e., be biased to have minimalresistance from drain to source) or turned off to open the switch (i.e.,be biased to have substantial resistance between drain and source). Itshould be noted that the “switch” can be of any form, including anabsorptive switch, a reflective open switch (as shown) or a reflectiveshort. In some such embodiments, the switches are opened and closed bysignals generated by the switch control processor 136. The signalgenerated to control a particular is coupled to the gate of that switch.The logical state of the signals coupled to the switches determineswhether the switch is open or closed.

In some embodiments, samples of the signals coupled to each of theinputs LB_IN1-3 and HB_IN1-3 are provided to the switch controlprocessor 136. For the sake of simplicity, connections between theinputs LB_IN1-3, HB_IN1-3 are not shown. Nonetheless, in someembodiments, the samples are analyzed to determine the amount of powerin each frequency band of interest. The processor then determines whichswitches are to be closed and which open based on the amount of power ineach frequency for each signal present at the inputs LB_IN1-3 andHB_IN1-3. For example, if signals applied to the input LB_IN1 is theonly LB input having a significant amount of power in the frequencybands to which the LB amplifier is tuned to operate (i.e., the LBfrequency bands), then the switch control processor 136 closes theswitch 207 between the LB_IN1 input and the LB LNA input. If more thanone input LB_IN1-3 has a significant amount of power within the LBfrequency band, then algorithms executed by the switch control processorcan determine which signals to select to be couple to the LB LNA input(i.e., whether to close switch 203, 205 or 207). In some embodiments,the algorithm may select based on the input that has the most powerwithin the LB frequency bands. In another embodiment, the algorithm mayselect the input that has the least out-of-band signal power (i.e.,power outside the LB frequency bands). In yet another embodiment, theswitch control processor 136 selects the input to be coupled to the LBLNA based on a preprogrammed hierarchy. That is, LB_IN1 is coupled tothe LB LNA input if there is a signal present having power within the LBfrequency bands that is above a threshold, regardless of the signalsapplied to the LB_IN2 input and the LB_IN3 input. Otherwise, if a signalis present at the LB_IN2 input that has power within the LB frequencybands that is above a threshold, LB_IN2 is coupled to the LB LNA input.It should be clear that several such algorithms can be implemented bythe switch control processor 136, including algorithms having multiplethresholds to determine the relative priority of each input LB_IN1-3. Insome embodiments, a low frequency primary signal is routed to LB_IN1 oralternatively, a high frequency primary signal is routed to HB_IN1. TheAUX port is routed to whichever of the two LNAs is unused (i.e., the HBLNA if the primary signal is a low frequency signal and the LB LNA ifthe primary signal is a high frequency signal) in order to “monitor” theentire spectrum.

Alternatively, mechanical switches or other input devices can be used toallow a user to indicate whether each switch should be open or closed.Still further, a remote switch control processor (not shown) thatresides in another part of a system in which the LNAIC 100 residesprovides signals that control the switches.

The output 134 of the LB band-select switch 128 is coupled to the inputof the LB LNA 122. In some embodiments, the LB LNA 122 is a simplecascode amplifier having an input FET 204 arranged in a common sourceconfiguration coupled to an output FET 206 arranged in a common gateconfiguration. The source of the output FET 206 is coupled to the drainof the input FET 204. The output 134 of the LB band-select switch 128 iscoupled to the gate of the input FET 204. In some embodiments, the LBLNA 122 is an amplifier having a single FET 204 arranged in a commonsource configuration. In yet other embodiments, the LB LNA 122 is anamplifier having multiple common-gate devices (e.g., FETs) in a stackeddevice configuration.

In some embodiments, a bias/control voltage is applied to the gate ofthe output FET 206. The bias/control voltage can be used to turn the LBLNA 122 on or off, as well as ensure that the LB LNA 122 is biased tooperate in a linear operating region when turned on. In someembodiments, the bias/control voltage is generated by the switch controlprocessor 136. Alternatively, the bias/control voltage is applied andremoved by opening or closing a switch (not shown) coupled between abias/control voltage source and the gate of the output FET 206. In someembodiments, such a switch is controlled by the switch control processor136. Still further, the bias/control voltage is generated external tothe LNAIC 100 and coupled to a port of the LNAIC 100. The drain of theoutput FET 206 is coupled to a supply voltage (VDD). An inductance 208and a capacitance 210 are placed in parallel between the drain of theoutput FET 206 and the voltage source VDD. The output of the LB LNA 122is taken from the drain of the output FET 206. An output capacitor 211is placed in series between the drain of the output FET 206 and the LNAoutput 216.

In some embodiments, an electrical conductor that couples the output ofthe LB band-select switch 128 to the gate of the LB LNA 122 has aninductance 212 that can be modeled as a lumped inductance. In addition,in some embodiments, a direct current (DC) blocking capacitor 214 isprovided to ensure proper biasing of the input FET 204. A degenerationinductance 218, which in some embodiments is the inherent inductance ofa conductor, is placed between the source of the input FET 204 andground.

By selecting between the three inputs LB_IN1-3, the LB band-selectswitch 128 can select which input is to be routed to the LB LNA inputand amplified by the LNAIC 100. Likewise, the HB band-select switch 124can select which input HB_IN1-3 is to be routed to the input of the HBLNA 120.

FIG. 3 is a simplified block diagram of another embodiment of an LNAIC300. The LNAIC 300 has six input ports HB_IN1-3 and LB_IN1-3, similar tothe LNAIC 100. The first three input ports HB_IN1-3 to the LNAIC arecoupled to an HB band-select switch 302. The other three input portsLB_IN1-3 are coupled to an LB band select switch 303. The first inputHB_IN1 to the LNAIC 300 is coupled to a first HB bandpass filter 316.The second input HB_IN2 to the LNAIC 300 is coupled to a second HBbandpass filter 318. Similar to the bandpass filters 116, 118 discussedwith respect to the LNAIC 100, each of the HB bandpass filters 316, 318are tuned to a unique frequency band for which the HB LNA 308 isoptimized. Each of the LB bandpass filters 328, 330 is tuned to a uniquefrequency band for which the LB LNA 332 is optimized. An AUX input port305 is coupled to the HB_IN3 and LB_IN3 inputs to the LNAIC 300. In analternative embodiment, the LNAIC 300 has an AUX input that is coupledto the HB_IN3 input of the HB band-select switch 302 and also to theLB_IN3 input of the LB band-select switch 303. That is, the LNAIC 300has a single connection to the AUX input 305.

The HB band-select switch 302 has two outputs 304, 306. The HBband-select switch 302 can select the signals applied to any of thethree inputs HB_IN1-3 and couple the selected signals to the firstoutput 304. The first output 304 is coupled to the input of an HB LNA308. The output of the HB LNA is coupled to a first of two inputs 310,312 to an HB output switch 314.

The second output 306 of the HB band-select switch 302 is coupled to asecond input 312 of the HB output switch 314. As is the case with thefirst output 304, the HB band-select switch 302 can select the signalsapplied to any of the three inputs HB_IN1-3 and couple the selectedsignals to the second output 306. Similar to the HB band-selector switch302, the LB band-selector switch 303 has two outputs 316, 318. The firstoutput 316 is coupled to the input of an LB LNA 320. The second output318 of the LB band-select switch 303 is coupled to a second input 324 ofan LB output switch 326. The output of the HB LNA 320 is coupled to afirst input 322 to the LB output switch 326.

FIG. 4 is a more detailed illustration of the LNAIC 300. The twoband-select switches 302, 303, LNAs 308, 322 and output switches 314,326 are essentially identical. Accordingly, only the low band (LB)components (i.e., LB band-select switch 303, LB LNA 322 and LB outputswitch 326) are discussed. Nonetheless, in some embodiments, each of thecomponents 302, 303, 314, 326 is optimized to operate in the frequencyrange for which the associated LNA 308, 322 is optimized to operate.

The LB band-select switch 303 has seven internal switches 402, 404, 406,408, 410, 412, 414. The first three switches 402, 404, 406 provide apath for the LB band-select switch 303 to couple one of the three inputsLB_IN1-3 to the input of the LB LNA 322 (i.e., “select” signals appliedto one of the input ports). The next three switches 408, 410, 412provide a path for the LB band-select switch 303 to couple one of theinputs LB_IN1-3 directly to the second input 324 of the LB output switch326. In some embodiments, only one of the first six switches 402, 404,406, 408, 410, 412 is turned on at a time. Accordingly, signals fromonly one of the inputs LB_IN1-3 are coupled to the LB LNA 332 ordirectly to the second input of the LB output switch 324, but not both.In some alternative embodiments, a combination of the switches can beactivated (i.e., closed) and the output switches 314, 326 can select thesignal to be routed to the output.

In addition, the seventh switch 414 within the LB band-select switch 303provides a path from the input 416 of the LB LNA to ground. The switch414 is closed when each of the three switches 402, 404, 406 are open.Shorting the input of the LB LNA 332 to ground better controls theimpedance of the LB LNA when it is not in use, and reduces the risk ofunwanted impedances getting closer to short negatively impacting the HBLNA performance. In addition, in some embodiments, a bias/controlvoltage is applied to the gate of an output FET 418 to turn the LB LNA332 off when all of the switches 402, 404, 406 are open. The LB outputswitch 326 has three internal switches 420, 422, 424. For the sake ofsimplicity each of the switches 402, 404, 406, 408, 410, 412, 420, 422,424 are shown as simple single pole, single throw switches. However, insome embodiments, similar to the LNAIC 100 discussed above, all of theswitches in the LNAIC 300 are implemented using FETs that can be turnedon to close the switch or turned off to open the switch. In some suchembodiments, the switches are opened and closed by signals generated bythe switch control processor 336. The signal generated to control aparticular is coupled to the gate of that switch. The logical state ofthe signals coupled to the switches determines whether the switch isopen or closed. Similar to the LNAIC 100 discussed above, in someembodiments the signals applied to the inputs LB_IN1-3, HB_IN1-3 aresampled and the samples are coupled to the switch control processor 336for analysis in order to allow the switch control processor 336 todetermine how to set the switches 402, 404, 406, 408, 410, 412, 420,422, 424. Alternatively, the control signals can be provide in any ofthe ways discussed above with regard to the LNAIC 100. In someembodiments, the inputs to each switch can be selectively terminatedwhen unused using an Absorptive or Reflective Short shunt switch arm. Ifthe signals are sampled and the samples are coupled to the switchcontrol processor 336 for analysis, a determination can be made that theinput is unused.

In some embodiments, either the first switch 420 or the second switch422 is closed to provide a path either from the output of the LB LNA 332to the LNAIC output, or alternatively, from the one of the inputsLB_IN1-3 to the LNAIC output when one of the switches 408, 410, 412 areclosed within the LB band-select switch 303. The third switch 424 is anLB ground switch that provides a path from the second input 324 toground. The LB ground switch 424 may be closed when the LB LNA 332 isinactive (i.e., the AUX input is coupled to the HB LNA 308 or signalsare applied to the HB_IN1 input or HB_IN2 input and no signals areapplied to the LB_IN1 input or LB_IN2 input). In that case, the switch402 coupled to the LB_IN3 port is open. In some embodiments, theswitches 404, 406 are also open when the HB LNA 308 is active. Byclosing the LB ground switch 424 when none of the switches 408, 410, 412in the LB band-select switch are closed, the impedance at the nodebetween switch 303 and switch 324 can be better controlled. Thus, thelikelihood of unwanted resonance or oscillations can be reduced oreliminated.

The LB LNA 332 and HB LNA 308 are essentially the same as the LB LNA 122and HB LNA 120 described above with respect to the LNAIC 100 of FIG. 1and FIG. 2.

Methods

FIG. 5 is a flowchart illustrating a method 500 for efficientlyamplifying signals coupled to an auxiliary (AUX) input, wherein thesignals can be in any frequency band selected from a broad range offrequency bands. Initially, an AUX input is provided (STEP 502). The AUXinput is coupled to at least a first and second band-select switch (STEP504). At least a first and second LNA are provided, each tuned tooperate over a unique frequency range (STEP 506). Each LNA is coupled toa corresponding one of the band select switches. The first and secondband-select switches are controlled to route signals applied to the AUXinput to one of the LNAs (STEP 508). In one embodiment, the methodfurther includes controlling the LNA to which signals from the AUX inputis coupled by applying a bias/control voltage to the gate of an outputFET within the LNA (STEP 510). In some embodiments, the step ofcontrolling the band-select switches includes determining whethersignals applied to the AUX input are within an LB frequency band towhich an LB LNA has been tuned to operate or an HB frequency band towhich an HB LNA has been tuned to operate.

FIG. 6 is a flowchart of another method 600 for efficiently amplifyingsignals coupled to an AUX input, wherein the signals can have anyfrequency from among a broad range of frequency bands. Initially, step502 through step 508 are performed similar to the method 500 of FIG. 5.In addition, the method 600 further includes providing at least oneoutput switch, each output switch associated with a band-select switch,LNA and LNAIC output (STEP 602). The outputs of a band-select switch aregrounded when the associated LNA is not active (STEP 604). In someembodiments, the method further includes controlling the output switchto couple either the output of the associated LNA or an output of theassociated band-select switch to an associated LNAIC output (STEP 606).

Fabrication Technologies and Options

The term “FET” means any transistor that has an insulated gate whosevoltage determines the conductivity of the transistor. Variousembodiments may be implemented in any suitable IC technology or inhybrid or discrete circuit forms. For example, embodiments may befabricated using any suitable substrates and processes, including butnot limited to standard bulk silicon, silicon-on-insulator (SOI),silicon-on-sapphire (SOS), bipolar, BiCMOS, SiGe HBT, GaAs HBT, GaNHEMT, GaAs pHEMT, and MESFET technologies. However, the conceptsdescribed above are particularly useful with an SOI-based fabricationprocess (including SOS), and with fabrication processes having similarcharacteristics.

A number of embodiments have been described. It is to be understood thatvarious modifications may be made without departing from the spirit andscope of the claimed invention. For example, voltage polarities may bereversed depending on a particular specification and/or implementingtechnology (e.g., NMOS, PMOS, CMOS, or BJT and enhancement mode ordepletion mode transistor devices). Component voltage, current, andpower handling capabilities may be adapted as needed, for example, byadjusting device sizes, serially “stacking” components (particularlyFETs) to withstand greater voltages, and/or using multiple components inparallel to handle greater currents. In addition, some of the stepsdescribed above may not be dependent on the order in which they areperformed, and thus can be performed in an order different from thatdescribed above. Further, some of the steps described above may beoptional. Various activities described with respect to the methodsidentified above can be executed in repetitive, serial, or parallelfashion. Furthermore, throughout the disclosure, switches can beimplemented as absorptive, reflective open or reflective short devices.Still further, it should be noted that while two bands are shownthroughout the disclosure, any number of bands are within the scope ofthe disclosed method and apparatus. Accordingly, any number ofband-select switches and associated LNAs and output switches may beincluded. Similarly, each band select-switch can select to couple anynumber of inputs to any number of outputs.

Furthermore, although the disclosed method and apparatus is describedabove in terms of various examples of embodiments and implementations,it should be understood that the particular features, aspects andfunctionality described in one or more of the individual embodiments arenot limited in their applicability to the particular embodiment withwhich they are described. Thus, the breadth and scope of the claimedinvention should not be limited by any of the examples provided indescribing the above disclosed embodiments.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide examples of instances of the item indiscussion, not an exhaustive or limiting list thereof; the terms “a” or“an” should be read as meaning “at least one,” “one or more” or thelike; and adjectives such as “conventional,” “traditional,” “normal,”“standard,” “known” and terms of similar meaning should not be construedas limiting the item described to a given time period or to an itemavailable as of a given time, but instead should be read to encompassconventional, traditional, normal, or standard technologies that may beavailable or known now or at any time in the future Likewise, where thisdocument refers to technologies that would be apparent or known to oneof ordinary skill in the art, such technologies encompass those apparentor known to the skilled artisan now or at any time in the future.

A group of items linked with the conjunction “and” should not be read asrequiring that each and every one of those items be present in thegrouping, but rather should be read as “and/or” unless expressly statedotherwise. Similarly, a group of items linked with the conjunction “or”should not be read as requiring mutual exclusivity among that group, butrather should also be read as “and/or” unless expressly statedotherwise. Furthermore, although items, elements or components of thedisclosed method and apparatus may be described or claimed in thesingular, the plural is contemplated to be within the scope thereofunless limitation to the singular is explicitly stated.

The presence of broadening words and phrases such as “one or more,” “atleast,” “but not limited to” or other like phrases in some instancesshall not be read to mean that the narrower case is intended or requiredin instances where such broadening phrases may be absent. The use of theterm “module” does not imply that the components or functionalitydescribed or claimed as part of the module are all configured in acommon package. Indeed, any or all of the various components of amodule, whether control logic or other components, can be combined in asingle package or separately maintained and can further be distributedin multiple groupings or packages or across multiple locations or acrossmultiple technologies.

Additionally, the various embodiments set forth herein are describedwith the aid of block diagrams, flow charts and other illustrations. Aswill become apparent to one of ordinary skill in the art after readingthis document, the illustrated embodiments and their variousalternatives can be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration.

What is claimed is:
 1. A low noise amplifier integrated circuit (LNAIC)comprising: a first low noise amplifier (LNA) having an input and anoutput; a second LNA having an input and an output; a first input selectswitch having at least two inputs, at least one input being an auxiliary(AUX) input, the input select switch configured to couple at least oneof the inputs to the first LNA input; and an second input select switchhaving at least two inputs, including at least one AUX input, the secondinput select switch configured to couple at least one of the inputs tothe second LNA input; wherein the AUX input of the first select switchis coupled to the AUX input of the second select switch.
 2. The LNAIC ofclaim 1, wherein: the first LNA is a low band (LB) LNA tuned foroperation in an LB frequency range, the LB LNA having an input and anoutput; the second LNA is a high band (HB) LNA tuned for operation in acorresponding HB frequency range, the HB LNA having an input and anoutput; the first input select switch is a LB band-selectswitchconfigured to receive signals within the LB frequency range; andthe second input select switch is an HB band-select switch configured toreceive signals within the HB frequency range
 3. The LNAIC of claim 2,wherein the LB band-select switch configured to couple the AUX input tothe LB LNA input upon receiving, at the AUX input, signals within the LBfrequency range and the HB band-select switch configured to couple theAUX input to the corresponding HB LNA upon receiving, at the AUX input,signals within the HB frequency range.
 4. A low noise amplifierintegrated circuit (LNAIC) comprising: an LB low noise amplifier (LNA)tuned for operation in an LB frequency range and having an input and anoutput; an HB LNA tuned for operation in a corresponding HB frequencyrange and having an input and an output; an LB band-select switch havingat least one input configured to be coupled to an auxiliary (AUX) inputof a front-end module, the LB band-select switch including an firstswitch coupled between the AUX input and the LB LNA, wherein the firstswitch is closed upon receiving, at the AUX input, signals within the LBfrequency range; and an HB band-select switch having at least one inputcoupled to the AUX input, the HB band-select switch including a firstswitch coupled between the AUX input and the corresponding HB LNA,wherein the first switch is closed upon receiving, at the AUX input,signals within the HB frequency range.
 5. The LNAIC of claim 4, wherein:the LB band-select switch includes a second input configured to receivesignals that are within a first band within the LB frequency range; theLB band-select switch includes at least a second switch coupled betweenthe second input and the first LNA; a second input to the HB band-selectswitch is configured to receive signals that are within a first band ofthe HB frequency range; and the HB band-select switch includes secondswitch coupled between the second input and the input to the HB LNA. 6.The LNAIC of claim 5, further including: a third input to the LBband-select switch configured to receive signals that are within asecond band of the LB frequency range; a third switch within the LBband-select switch, coupled between the input to the LB LNA and thethird input to the LB band-select switch; a third input to the HBband-select switch configured to receive signals that are within asecond band of the HB frequency range; and a third switch within the HBband-select switch, coupled between the third input and the HB LNA. 7.The LNAIC of claim 4, further including a switch control processorcoupled to the LB band-select switch and to the HB band-select switch toopen and close the first switch in the LB band-select switch and to openand close the first switch in the HB band-select switch.
 8. The LNAIC ofclaim 4, further including: at least one additional LNA tuned foroperation in a corresponding frequency range and having an input and anoutput; at least one additional band-select switch having a plurality ofinputs, including at least one input configured to be coupled to theauxiliary (AUX) input of a front-end module, the at least one additionalband-select switch including an first switch coupled between the AUXinput and a corresponding one of the at least one additional LNAs,wherein the first switch is closed upon receiving, at the AUX input,signals within the corresponding frequency range.
 9. The LNAC of claim4, further including: an LB output switch having a first and secondinput and an output, the LB output switch having a first switchconfigured to selectively provide a path from the first input to theoutput or alternatively, from the second input to the output and havinga second switch coupled between the first input and ground toselectively provide a path from the first input to ground; and an HBoutput switch having a first and second input and an output, the HBoutput switch having a first switch configured to selectively provide apath from the first input to the output or alternatively, from thesecond input to the output and having a second switch coupled betweenthe first input and ground to selectively provide a path from the firstinput to ground; wherein: the first input of the LB output switch iscoupled to the LB LNA output; the second input to the LB output switchis coupled to a second output of LB band-select switch; the LBband-select switch has a second switch to selectively provide a pathbetween the AUX input and the second output from the LB band-selectswitch.
 10. The LNAIC of claim 9, wherein: the LB band-select switchfurther includes a third switch coupled between the first output of theLB band-select switch and ground; and the HB band-select switch furtherincludes a third switch coupled between the first output of the HBband-select switch and ground.
 11. A method for efficiently amplifyingsignals coupled to an auxiliary (AUX) input of a front-end module,including: providing an AUX input to the front-end module; providing alow band (LB) band-select switch and a high band (HB) band-selectswitch; coupling the AUX input to an input of both the LB band-selectswitch and the HB band-select switch; providing an LB low noiseamplifier (LNA) tuned to operate in an LB frequency range and a HB LNAtuned to operate in an HB frequency range; controlling the LBband-select switch and the HB band-select switch to route signalsapplied to the AUX input to one of the LB LNA or the HB LNA.
 12. Themethod of claim 11, further wherein controlling the LB band-selectswitch and the HB band-select switch includes selecting between therouting the signals from the AUX input to the LB LNA if the signalsapplied to the AUX input are in the LB frequency range and to the HB LNAif the signals are in the HB frequency range.
 13. The method of claim11, further including: providing a dedicated LB input for LB frequencysignals; providing a dedicated input for HB frequency signals; couplingthe dedicated LB input to the LB LNA when signals within the LBfrequency range are applied to the dedicated LB input; and coupling thededicated HB input to the HB LNA when signals within the HB frequencyrange are coupled to the HB input.
 14. The method of claim 13, furtherincluding: grounding the input to the LB LNA when the LB LNA is notactive; and grounding the input to the HB LNA when the HB LNA is notactive.
 15. The method of claim 14, further including: grounding theoutputs from the LB band-select switch when the LB LNA is not active;and grounding the outputs from the HB band-select switch when the HB LNAis not active.